613 research outputs found
Monitoring osteoarthritis: a cross-sectional survey in general practice
<b>Background</b> Despite being a highly prevalent chronic condition managed predominantly in primary care and unlike other chronic conditions, osteoarthritis (OA) care is delivered on an ad hoc basis rather than through routine structured review. Evidence suggests current levels of OA care are suboptimal, but little is known about what general practitioners' (GPs) consider important in OA care, and, thus, the scope to improve inconsistency or poor practice is, at present, limited.<p></p>
<b>Objectives</b> We investigated GPs' views on and practice of monitoring OA. <p></p>
<b>Methods</b> This was a cross-sectional postal survey of 2500 practicing UK GPs randomly selected from the Binley's database. Respondents were asked if monitoring OA patients was important and how monitoring should be undertaken.<p></p>
<b>Results</b> Responses were received from 768 GPs of whom 70.8% were male and 89.5% were principals within their practices. Despite 55.4% (n = 405) indicating monitoring patients with OA was important and 78.3% (n = 596) considering GPs the appropriate professionals to monitor OA, only 15.2% (n = 114) did so routinely, and 45% (n = 337) did not monitor any OA patients at all. In total, 61.4% (n = 463) reported that patients should self-monitor. Respondents favored monitoring physical function, pain, and analgesia use over monitoring measures of BMI, self management plans, and exercise advice.<p></p>
<b>Conclusions</b> The majority of respondents felt that monitoring OA was important, but this was not reflected in their reported current practice. Much of what they favored for monitoring was in line with published guidance, suggesting provision of suboptimal care does not result from lack of knowledge and interventions to improve OA care must address barriers to GPs engaging in optimal care provision
Flutter and forced response of mistuned rotors using standing wave analysis
A standing wave approach is applied to the analysis of the flutter and forced response of tuned and mistuned rotors. The traditional traveling wave cascade airforces are recast into standing wave arbitrary motion form using Pade approximants, and the resulting equations of motion are written in the matrix form. Applications for vibration modes, flutter, and forced response are discussed. It is noted that the standing wave methods may prove to be more versatile for dealing with certain applications, such as coupling flutter with forced response and dynamic shaft problems, transient impulses on the rotor, low-order engine excitation, bearing motion, and mistuning effects in rotors
Geometry of Frictionless and Frictional Sphere Packings
We study static packings of frictionless and frictional spheres in three
dimensions, obtained via molecular dynamics simulations, in which we vary
particle hardness, friction coefficient, and coefficient of restitution.
Although frictionless packings of hard-spheres are always isostatic (with six
contacts) regardless of construction history and restitution coefficient,
frictional packings achieve a multitude of hyperstatic packings that depend on
system parameters and construction history. Instead of immediately dropping to
four, the coordination number reduces smoothly from as the friction
coefficient between two particles is increased.Comment: 6 pages, 9 figures, submitted to Phys. Rev.
Organic and conventional tomato cropping systems.
Among several alternative agricultural systems have been developed, organic agriculture has deserved increasing interest from. The objective of this paper was comparing both organic (OS) and conventional (CS) tomato cropping systems for varieties Débora and Santa Clara, through an interdisciplinary study. The experiment was set up in a randomized blocks design with six replicates, in a dystrophic Ultisol plots measuring 25 ´ 17 m. Cropping procedures followed by either local conventional or organic growers practices recommendations. Fertilization in the OS was done with organic compost, single superphosphate, dolomitic limes (5L, 60 g, and 60 g per pit), and sprayed twice a week with biofertilizer. Fertilization in the CS was done with 200 g 4-14-8 (NPK) per pit and, after planting, 30 g N, 33 g K and 10.5 g P per pit; from 52 days after planting forth, plants were sprayed once a week with foliar fertilizer. In the CS, a blend of insecticides, fungicides and miticides was sprayed twice a week, after planting. In the OS, extracts of black pepper, garlic, and Eucalyptus; Bordeaux mixture, and biofertilizer, were applied twice a week to control diseases and pests. Tomato spotted wilt was the most important disease in the OS, resulting in smaller plant development, number of flower clusters and yield. In the CS, the disease was kept under control, and the population of thrips, the virus vector, occurred at lower levels than in the OS. Variety Santa Clara presented greater incidence of the viral disease, and for this reason had a poorer performance than 'Débora', especially in the OS. Occurrence of Liriomyza spp. was significantly smaller in the OS, possibly because of the greater frequency of Chrysoperla. The CS had smaller incidence of leaf spots caused by Septoria lycopersici and Xanthomonas vesicatoria. However, early blight and fruit rot caused by Alternaria solani occurred in larger numbers. No differences were observed with regard to the communities of fungi and bacteria in the phylloplane, and to the occurrence of weeds
The Role of Friction in Compaction and Segregation of Granular Materials
We investigate the role of friction in compaction and segregation of granular
materials by combining Edwards' thermodynamic hypothesis with a simple
mechanical model and mean-field based geometrical calculations. Systems of
single species with large friction coefficients are found to compact less.
Binary mixtures of grains differing in frictional properties are found to
segregate at high compactivities, in contrary to granular mixtures differing in
size, which segregate at low compactivities. A phase diagram for segregation
vs. friction coefficients of the two species is generated. Finally, the
characteristics of segregation are related directly to the volume fraction
without the explicit use of the yet unclear notion of compactivity.Comment: 9 pages, 6 figures, submitted to Phys. Rev.
Statistics of the contact network in frictional and frictionless granular packings
Simulated granular packings with different particle friction coefficient mu
are examined. The distribution of the particle-particle and particle-wall
normal and tangential contact forces P(f) are computed and compared with
existing experimental data. Here f equivalent to F/F-bar is the contact force F
normalized by the average value F-bar. P(f) exhibits exponential-like decay at
large forces, a plateau/peak near f = 1, with additional features at forces
smaller than the average that depend on mu. Computations of the force-force
spatial distribution function and the contact point radial distribution
function indicate that correlations between forces are only weakly dependent on
friction and decay rapidly beyond approximately three particle diameters.
Distributions of the particle-particle contact angles show that the contact
network is not isotropic and only weakly dependent on friction. High
force-bearing structures, or force chains, do not play a dominant role in these
three dimensional, unloaded packings.Comment: 11 pages, 13 figures, submitted to PR
Sun exposure behaviour, seasonal vitamin D deficiency, and relationship to bone health in adolescents
YesContext: Vitamin D is essential for bone health in adolescence, where there is rapid bone mineral
content accrual. As cutaneous sun-exposure provides vitamin D, there is no recommended oral intake
for UK adolescents.
Objective: Assess seasonal vitamin D status and its contributors in white Caucasian adolescents, and
examine bone health in those found deficient.
Design: Prospective cohort study.
Setting: Six schools in Greater Manchester, UK.
Participants: 131 adolescents, 12–15 years.
Intervention(s): Seasonal assessment of circulating 25-hydroxyvitamin D (25OHD), personal sunexposure
and dietary vitamin D. Adolescents deficient (25OHD <10 ng/mL/25 nmol/L) in ≥one
season underwent dual-energy X-ray absorptiometry (lumbar spine, femoral neck), with bone mineral
apparent density (BMAD) correction for size, and peripheral quantitative computed tomography
(distal radius) for volumetric (v)BMD.
Main Outcome Measure: Serum 25OHD; BMD.
Results: Mean 25OHD was highest in September: 24.1 (SD 6.9) ng/mL and lowest in January: 15.5
(5.9) ng/mL. Over the year, 16% were deficient in ≥one season and 79% insufficient (25OHD <20
ng/mL/50 nmol/L) including 28% in September. Dietary vitamin D was low year-round while
personal sun-exposure was seasonal and predominantly across the school week. Holidays accounted
for 17% variation in peak 25OHD (p<0.001). Nineteen adolescents underwent bone assessment,
which showed low femoral neck BMAD versus matched reference data (p=0.0002), 3 with Z≤ -2.0
distal radius trabecular vBMD.
Conclusions: Sun-exposure levels failed to provide adequate vitamin D, ~one-quarter adolescents
insufficient even at summer-peak. Seasonal vitamin D deficiency was prevalent and those affected
had low BMD. Recommendations on vitamin D acquisition are indicated in this age-group.The Bupa Foundation (Grant number TBF-M10-017)
Historical, local and landscape factors determine the success of grassland restoration for arthropods
In Europe, extensively managed grasslands have undergone large-scale declines due to intensive agriculture and abandonment. Their restoration supports arthropod biodiversity within farming systems. We investigated limiting factors for arthropod establishment during grassland restoration across a chronosequence of 52 restoration sites established by either natural regenerating or direct seeding. Our study covered 363 arthropod species of 10 orders, including detritivores, herbivores, predators and pollinators. These were sampled using pitfall traps, suction sampling and transect walks. The similarity of plant communities on restoration sites to target species rich grasslands was positively correlated with the similarity of the arthropod communities to these same grasslands. There was evidence that restoration sites located in landscapes suffering from historic large-scale loss of species rich grassland (1930–2015) had lower success in replicating the composition of arthropod communities and supported the lowest levels of species richness. The age of the restoration site was a predictor of restoration success for some trophic levels. For example, predator species richness was greatest in the oldest restoration sites. However, this was only the case were sites were either of large size or located in landscapes with the lowest historic loss of species rich grassland. Impacts of within site management also affected arthropod communities. The annual frequency of cutting negatively affected detritivores species richness, and selected against traits including herbivore monophagy. Overall arthropod species richness was positively correlated with sward height. These results emphasise the relative importance of the success with which the floral community is replicated, as well as landscape and management factors, during grassland restoration. This has implications for future agri-environmental schemes. In particular, achieving high quality within-site management that maximises establishment of the plant communities needs to be the initial focus of any restoration program
Granular Solid Hydrodynamics
Granular elasticity, an elasticity theory useful for calculating static
stress distribution in granular media, is generalized to the dynamic case by
including the plastic contribution of the strain. A complete hydrodynamic
theory is derived based on the hypothesis that granular medium turns
transiently elastic when deformed. This theory includes both the true and the
granular temperatures, and employs a free energy expression that encapsulates a
full jamming phase diagram, in the space spanned by pressure, shear stress,
density and granular temperature. For the special case of stationary granular
temperatures, the derived hydrodynamic theory reduces to {\em hypoplasticity},
a state-of-the-art engineering model.Comment: 42 pages 3 fi
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